Magnetic disk storage file

ABSTRACT

A magnetic disk storage file employs a plurality of magnetic transducers for each recording disk surface, and at least one transducer is associated with each data track. The transducer assemblies are supported by racks, which are mounted in stacked fashion to pivotable posts. The posts are fixed in a precise position relative to the true axis of the spindle on which the storage disks are mounted for rotation. The posts are pivotable so that the transducer assemblies and racks may be retracted for easy replacement, and returned to the same precise position and alignment relative to the data disk surface, whereby each transducer bears the same relation to its associated data track as it had prior to retraction.

United States Patent 1 1 Hoehmann 1 1 MAGNETIC DISK STORAGE FILE [75]Inventor: Henry G. Hoehmann, Los Gatos,

Calif.

[73] Assignee: international Business Machines Corporation. Armonk. N.Y.[22] Filed: Mar. 18, 1970 (21] Appl. No.: 20,781

[521 US. Cl 360/98; 360/105 [51] 1nt.Cl ..G11c11/02 158] Field ofSearch... 340/174.1 C. 174.1 E. 74 M.

340/74 MD; 179/1002. 174.1 D

[56] References Cited UNITED STATES PATENTS 2.514.771 5/1978 Ehalt et a1340/174.1 C 2.961.494 11/1960 Darow. Jr. et a1 179/1002 3.082.406 3/1963Stevens 340/174.1 C 3.103.650 9/1963 Gehring.1r.et a1 340/1741 D3,177.493 4/1965 Durlosky 340/l74.1 E 3.187.317 6/1965 Smith. Jr340/174.1 C 3.320.599 5/1967 Billawala 340/1741 1 1 May 6, 197:

3.399.392 8/1968 Funazura 340/1741 3.478.341 11/1969 Trimble et a1.340/1741 3.480.936 11/1969 Gerlach et a1. 340/1741 PrimaryExaminer-Benedict V. Safourek Attorney, Agent. or Firm--Nathan N.Kallman [57] ABSTRACT A magnetic disk storage file employs a pluralityo: magnetic transducers for each recording disk surface and at least onetransducer is associated with eacl data track. The transducer assembliesare supported by racks. which are mounted in stacked fashion tcpivotableposts. The posts are fixed in a precise posi tion relative tothe true axis of the spindle on which the storage disks are mounted forrotation. The posts are pivotable so that the transducer assemblies andracks may be retracted for easy replacement. and returned to the sameprecise position and alignment relative to the data disk surface.whereby each transducer bears the same relation to its associated datatrack as it had prior to retraction.

12 Claims, 10 Drawing Figures MAGNETIC DISK STORAGE FILE gas. Thisarrangement was cumbersome and difficult t CROSS REFERENCE TO RELATEDAPPLlCATlON in us. Pat. No. 3.579.213 filed in bchalfof E. R. 80-SUMMARY OF THE NVENT'ON lyst. and assigned to the same assignee. amultigap mag- 5 An object of this invention is to provide a novel annetic head slider assembly is disclosed. which is particimpr d fix head.fixed disk ularly useful for fixed head files. The head assembly isAnother ject Of this n ention is to provide a 'iXC an integralstructure. having a plurality of transducing head disk fi erein two ormore head transducin elements or flux-sensing nonmagnetic gaps. whichare elements can be located over each data track and z uniformly spacedd li d fmscanning di lt) specific angular positions around the diskcircumfei data tracks. In the apparatus of the instant application.

a number of such air bearing head assemblies are em- Anmhcl' j Hlnvcmllm is Pmvldc a me pmycd i each i surface, head. fixed disk filewherein the individual magneu heads may be installed in a machinewithout position; BACKGROUND OF THE lNvli-N'liloN l5 adjustment atinstallation. to radial and circumferenti; Pick] f he rnvcmim positionalaccuracies greater than the sum of compt This invention relates to anovel magnetic disk storff y p age file. and in particular to a fixedhead. fixed disk file. m pmvldc fixed l fixed dis wherein a number ofmagnetic head assemblies. each me wlfcrcm i l f dmks be f having amultiplicity oi" transducer elements. may he yet mummmmg Sim: f' fprucisuiy lncmcd mpctmvcly in he same posimm wk position of eachtransducer element to tts associate tive to recording media surl'aces.surmcc P f Descrimim Ur he prim A" Another UhjCLl ts to provide asupport tor magnet:

head assemblies in a disk tile. whereby the write drive and readelectronics may he commonly shared by set eral head assemblies.

A further object is to provide a fixed head t'ile conti uration whichincludes means for maintaining a "clca air environment within themachine. when in opera tion or when being serviced.

According to this invention. a fixed head. fixed dis file includes aplurality olspaced coasially aligne magnetic disks. and a plurality ofhead assemhlit mounted to racks. which in turn are supported h pivotablcpost structures. The post structures allow th head assemblies to besimultaneously moved to pos tions adjacent to discrete record tracks onthe disks; t be simultaneously pivoted away from the disks so th:certain head assemblies may be removed and rcplacct without displacementof the other heads or the disk liy the same token. the disks may beinterchanged witl out affecting the head assemblies or their positions.I this tuanner. each head assembly and transducer Llt ment. or itsreplacement. will always hear the same Pt sition and attitude relativeto its associated disk surl'ac and track.

Also. by means otthis invention. one common circu Presently knownmagnetic disk storage tiles employ a multiplicity ol magnetic disks.which cooperate with magnetic transducers or heads for recording andplayback ol' data. The head assemblies may be of the accessing type.which are actuated radially relative to the disk surface to seek outselected tracks for recording 3 and retrieval ol'data. The random accessactuator-type file may use one magnetic head assembly for each disksurface. which is an economical arrangement. but does not achieve thefast access capability that may be realized il'cach data track has afixed transducer associated 35 therewith.

However. fixed head assemblies having transducing elements associatedwith each track of a disk storage file present a dil'ficulty when thehead assemblies are being replaced. because each replacement head assem-4t! hly must assume the same precise positional relationship relative tothe disk surface and a data track. as existed before the exchange wasmade. It not. the new transducer elements and their sensing gaps may notbe aligned properly relative to the associated disk surface 45 and datatrack. whereby data signal processing would be distorted and degraded.In prior art fixed head files.

ll mind he l card may be connected to a multiplicity of transductrelative to an associated track. and then individually ckmcms Sn hmduring finding playback adjust the other head assemblies radially. whilethe 1 m f rh elements will be operative with disks were rotating and thehead assemblies were opcrcircuit Anmhcr m i "w i -i f dug-c illlVL. illUHlCY it! ilL'lIlLVL filtllill lflk'illltlll ilL'L'lll'ilLlL'S til yup iInthy and ['Qfi'igcruti yn systg n flu nah LtLtltll inch or less. Tomake such at tt tains a clean air environment and substantially constatplicatcd and expensive mechanisms would be required. Mmwmmm i hi di mand the risk of damage caused by head disk intcrt'er- H cnce would existwhen shifting loaded heads on rotatmulil' RWHUN DRAWN;

ing disks. It would be advantageous to have a simple. The invention willbe described in greater detail wit inexpensive and convenient means forsimultaneous reference to [he figures ol' the drawing in which:

and accurate adjustment and control of head position. m FIG. I is anisotnctric view. partly b k away. t.

pitch. roll. skew. and un aded height. particularly for picting part ofan assembly of a fixed head. fixed di:

a plurality of flying heads in a fixed head tile. Also. it file inaccordance with this invention;

is desirable that retnovnl of disks. when nece ary. FltlS. 2n and 2h aretop uttd l'ront vlesrmrespectivel should not require the removal ol' thenondel'ective of a hub tool employed for positioning and aligning headassemblies in the storage t'ilc. M head mounting post structure.illustrated in the sit in prior known l'ixed head files. contaminationcon view of FIG. 2c;

trol in the disk head area was maintained by sealing the FIG. 3 is anisotnctric view of a post structure utililt entire area and prcssuri/ingthe interior witlra clean in the novel assembly;

FIG. 4 is a rear plan view of a portion of the post structure;

FIG. 5 is a side elevation schematic view. partly broken away.illustrating the relation between the disk drive spindle. the supportracks and mounted heads. and the pivotable post supporting such headracks;

HO. 6 is a schematic plan view. partly in block. depicting the headracks. electronic circuit card. and head selection circuitry;

FIG. 7 is an exploded view representing the relationship between thehead racks and an associated disk. and the post and electronic curdstructures. partially shown;

FIG. 8 is an enlarged isometric view of a head rack support; and

FIG. 9 is a schematic representation of the filtration and temperaturecontrol system utilized in this invention.

Similar numerals refer to similar elements throughout the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1. amagnetic disk storage file structure is illustrated. including asubstantially square housing or cage 10. in which a drive shaft orspindle i2 is centrally located. When the file is in operation. a stackof spaced magnetic disks 14 (see FIGS. 5, 9) or a disk pack is mountedto the spindle l2. and rotated relative to magnetic transducers 16 forrecording or playback of data. In this particular embodiment. thetransducers or head assemblies 16 are fixed (in rack supports 50)relative to the disk surfaces during operation of the storage file. sothat each data track has one associated transducer. or more. cooperatingtherewith. in a fixed head file type. one or more of the rack supports50 or disks may be removed conveniently for re placement purposes. as aresult of wear or defects.

it should be appreciated that in high density data systems wherein thedata bits are closely packed along a data track. and the data tracks areclosely spaced along the radial direction ofthe disk surface. if morethan one transducing element is located on each track to minimizewaiting time before reading the desired information; and it is requiredto read two or more tracks simultaneously. the need for accurate radialand circumferential alignment of each transducing element relative tothe other transducing elements is critical.

To this end. post structures l8 (shown enlarged and in greater detail inFIG. 3) that support the head assemblies are positioned precisely atpredetermined locations relative to the spindle 12. to which the storagedisks l4 are coaxially mounted. To accomplish this precise positioning.a hub tool 20 (see FIGS. 2a. b) is seated to a flange 22 of the spindlel2. centered to the spindle by a collar formed in a recess at the top ofthe spindle. and fastened to the spindle by bolting. for example. Afixture 24. having a depressihle spring-loaded pin 26. is positioned ina keyed recess 28 in the top surface of the housing l0. and the hub tool20 and rotary spindle 12 are manually rotated. until the pin 26 engagesan aperture 30a or 30b in the hub tool periphery. At this time. the hubtool is locked in a stationary indexed position. if positioned bylocking the pin 26 in aperture 300. the hub tool will serve to locateand align two post structures at the rear corners of the cage and on theother hand. ifaperture 30b is engaged by the pin 26. two post structuresat the front corners of the cage may be located and aligned.

With the hub tool so positioned and locked. a set of vertically spaceddowel pins 32-1 for one post position (or 32-2 for another postposition. preferably displaced 90). that project from the hub tool. aremeshed with vertically spaced guide holes 34 (only the upper one beingshown in FIG. 4) formed in the rear surface of a post structure 18. Thisserves to position the post structure vertically and circumferentiallyrelative to the file housing 10 and the disk spindle 12. while thesurfaces on tool 20. from which the pins 32-1 and 32-2 protrude. serveto locate each post 18 radially from the true rotational axis of spindle12. The squareness or skew of the post l8 to a radial line from therotational axis of spindle 12 is also established by setting the facesof the posts 18 against the surfaces on tool 20 from which the pins 32-]and 32-2protrude.

With a post 18 so located and fastened to the hub tool 20. the postpivot bearings 36 are bolted to the cage at the threaded holes 40 whilethe outer races of these bearings are held loosely in split housings 35.Then the clamping screws in these housings are tightened to clamp theouter races of bearings 36 to the housings 35. With the outer races ofpost pivot bearings 36 clamped to the posts 18 and the inner racesclamped to the cage 10. the post pivot axis will be fixed. The poststructures also incorporate stop brackets 44 containing sphericalbearings 38, and the inner race of such bearing 38 is movable to engagea cage stop 42 which will determine at which radial location the postwill be fixed during transducing operation. When the inner race contactssuch cage stop 42. a threaded screw is inserted within the inner race tohold the previously slidable bearing 38 in place. Thereafter. a screw isinserted to clat ip a split housing 44 that encompasses the stop bearing38 so that the position of the bearing will be fixed. and will bear apermanent relation to the cage stop. This screw in the side of the splithousing is per manently retained in position. so that whenever the poststructure is pivoted away from the disk area and then returned forrecording or playback modes. the inner race of bearing 38 will abut thecage stop at exactly the same position. ensuring that the post will belocated having the same relation to the spindle axis as it previouslyhad. The post assembly 18 may now be unbolted from the hub tool 20. andthe dowel pins 32 may be disengaged from the post dowel holes 34.

A second set of post structures 18 spaced 90 apart may be inserted in asimilar manner. by releasing the pin 26 from aperture 300. and rotatingthe hub tool to engage the other aperture 30b with the pin 26. Thus.four post structures circumferentially spaced apart are located withpermanent radial. circumferential. height. and skew relationshipsrelative to the true spindle axis.

As illustrated in FIG. 4, the post structures 18 have dowels 46. andmounting holes 48 which cooperate with screws 49 attached to the racks.for accommodating rack supports 50 to which the head assemblies 16 aremounted. in this particular embodiment. the rack supports each carry twomultielement head slider assemblies 16 which have been preciselypositioned relative to the rectangular rack configuration and the racksurface. The air bearing head assemblies. which are disclosed in theaforementioned U.S. Pat. No. 3.579.213 are aligned optically toreference surfaces of the rack.

and are adjusted for unloaded height. skew. pitch. roll. and trackadjustments of screws 52'(see FIG. 8) in a manner known to those skilledin the art. The head assembly module is positioned on a rack platform 50so that each transducing gap has a defined position relative to thedatum surface of the rack.

Each head assembly 16 is formed to provide a number of transducingelements and sensing gaps. the gaps being aligned so that when the headassemblies are disposed adjacent to a disk surface. each transducingelement found on a rack support 50 is in'transducing relationship with adifferent data track. In effect. the transducing elements on racksupport 50 are serially aligned radially to the disk surface. in onepreferred embodiment. the elements of the racks supported by one post 18at the front of the housing may be positioned over tracks that alternatewith the tracks associated with the head elements mounted to the otherfront post. while the elements mounted to the two posts at the rear ofthe housing have the same relationship to each other. but serve tooperate in parallel with transducing elements at the front of the file.over the same data tracks. to achieve faster access.

A multiplicity of racks 50 are mounted vertically onto the posts 18. bymeans of the dowels 46 and guide holes 48. and are fastened to the postassembly by screw means that pass through the guide holes 48. it shouldbe noted that the head racks 50 may be joined to the posts 18 before orafter the posts are placed in the file housing l0. However. if the posts18 have been first joined to the housing 10, then the post structuresare released from the cage stops 42 to enable pivoting of the posts awayfrom the disk area. to allow seating the head assembly racks in avertical array along the length of the post.

Similarly. for maintenance and service. any head rack 50 may he removedby loosening the post stop 40 from the cage stop 42. and swinging thepost on the pivot formed by the bearing. away from the disk area. Whenthe post is swung away from the disk area. all the head racks areavailable for individual servicing and replacement. Since the positionof each rack is defined by the post hole and dowel arrangement.substitute rack assemblies will have exactly the same relationship tothe post. and thus to the disks. as the rack assemblies which theyreplace. No special adjustments are requircd during the replacementprocess.

Once the post structures 18 are properly positioned in the housing 10.the posts are detached from the cage stops 42 and pivoted on thebearings 36 away from the disk area. The hub tool is then released fromthe spindle l2 and disks 14 are mounted to the spindle in a mannerdescribed in U.S. Pat. No. 3.587.073 filed in behalf of S. Ghose et al.and assigned to the same assignce as the present invention.

With the head racks 50 mounted to the posts [8. a circuit card 54 iscoupled through connector plugs 56 and tongs 58 to the electricalwindings of the head assemblies 16. as illustrated in FIGS. 6 and 7. Thecard 54 carries electrical circuitry and components for processingsignals to and from the magnetic heads 16. A logic selection circuit 60energizes selected ones of the transducer elements associated with theaddressed data tracks. in accordance with signals received from anexternal control unit or processor. The single common circuit card 54thus is connected so that it may operate with a selected one of thetransducing elements that is energized at any given time.

Another feature of this invention is illustrated in FIG. 9, wherein theenclosed housing 10 containing the disk assembly 14 is coupled in aclosed loop with a temperature control system 62. Air is exhausted fromthe disk area through exhaust tubes 64 and passed through therefrigeration and temperature control unit 62. where the temperature ofthe air is modified to maintain a substantially constant temperature.The processed air is then expelled by means of a blower 66 throughtubings 68 through a filter 70 back into the disk area. When the diskhousing 10 is opened for service. the exhaust paths 64 are closed. andthe blower 66 is allowed to draw air in directly from the externalenvironment from which it is passed through filter 70, blown through thedisk area. and out the accessed opening of disk housing 10. in this way.a positive air pressure in the disk chamber. and a directed flow out ofthe area to prevent dust and other contamination from entering thehead-disk chamber are maintained.

The inventive assembly also accommodates an air supply (not shown) thatpasses air through air vents 72 in the post structures to a bellows ordiaphragm that provides a suspension or floating effect to the airhearing. flying heads utilized in this embodiment.

it should be understood that the specific embodiment disclosed hereinmay be modified and varied within the scope of the invention. Forexample. other than four post structures may be used. Hinge pins orswivel posts may be employed in lieu of spherical pivot bearings. Thehead assemblies may comprise single element transducers aligned on arack. or multielement integral structures also aligned radially. orstepwise. for transducing operation. by way of example.

What is claimed is:

l. A fixerhead magnetic disk storage file comprising:

a housing;

a drive spindle defining a rotational axis positioned in said housing;

a plurality of magnetic disks mounted coaxially on said spindle. saiddisks having recording surfaces on which data tracks are formed;

at least one pair of pivotable post structures positioned 180 apart.aligned parallel to and spaced equally from said spindle axis;

a multiplicity of multi-element head assemblies mounted to said poststructures. each head assembly having a like number of transducingelements that are aligned radially relative to a respective disksurface. when the post structure is fixed for file operation and datasignal transducing;

the transducing elements of one post structure and those of the otherpost structure of said one pair being diametrically opposed and intransducing relation with the same data tracks to provide parallel datasignal operation so that faster access is achieved;

said post structures being pivotable so that said head assemblies may bemoved away and precisely back to the same positions such that saidtransducing elements are accurately aligned with the same data tracks asprior to rotation of the post structures.

2. A magnetic disk storage file as in claim I, wherein two pairs of poststructures are provided. each structure being spaced apart from theadjacent structures. and circumferentially around said spindle axis.

and a like number of rnulti-element head assemblies mounted to each poststructure. so that each disk surface coacts in transducing relation withat least four multi-head assemblies that are circumferentially andequally spaced about said axis.

3. A magnetic disk storage tile as in claim 2. wherein the transducingelements mounted to one post structure are positioned over one set ofdata tracks and the transducing elements mounted to adjacent poststructures are positioned over alternate interleaved data tracks.

4. In a magnetic disk storage tile as in claim 1. wherein said headassemblies are aligned in columns over said tracks. substantiallyparallel to the axis of said drive spindle.

5. In a magnetic disk storage file as in claim I. further including anumber of racks. each rack carrying a plurality of said head assembliesand transducing elements. said racks being fastened to said poststructttres.

6. in a magnetic disk storage tile as in claim I. including a pivotbearing assembly coupled to said housing and to said post structures.providing a pivot for said post structures.

7. In a magnetic disk storage file as in claim l. further includingcommon circuit means. and electrical conncctor means coupled to saidmultiplicity of magnetic head assemblies. said connector means couplingall of said head assemblies to said circuit means. so that selected onesof said transducing elements may be operative with said common circuitmeans at a given time.

8. In a magneticdisk storage tile as in claim 7.

wherein said common circuit means is mounted to said post structures;and including a logic selection circuit coupled to said head assemblies.so that any ones of said transducing elements may be selected to beenergized and form a closed circuit path in conjunction with saidcircuit means.

9. In a magnetic disk storage tile as in claim t. the combinationfurther including refrigeration and filtration means. providing an airflow and cooling through thedisk area. thereby maintaining a clean airenvironment and a substantially constant temperature.

[0. ln a magnetic disk storage tile as in claim 9. further including anenclosure for said file. said disks and head assemblies being disposedwithin said enclosure:

closed loop means coupled to said enclosure for eshausting air from thearea of said disks: and

temperature control means for maintaining the air within said enclosureat a substantially constant temperature. said closed loop meansproviding a positive air flow outwardly from said enclosure to ambientair when said enclosure is opened. to prevent entry of contaminants. I

ll. ln a magnetic disk storage file as in claim I. wherein said poststructures include air vents providing access for air flow to said headassemblies. so that said head assemblies fly in relation to said rotarydisks.

[2. lo a magnetic disk storage file as in claim I. including a hub toolproviding alignment means for said post structures relative to the axisof said drive spindle.

said hub tool being rotatable with saidspindle.

Q C I Q i

1. A fixed head magnetic disk storage file comprising: a housing; adrive spindle defining a rotational axis positioned in said housing; aplurality of magnetic disks mounted coaxially on said spindle, saiddisks having recording surfaces on which data tracks are formed; atleast one pair of pivotable post structures positioned 180* apart,aligned parallel to and spaced equally from said spindle axis; amultiplicity of multi-element head assemblies mounted to said poststructures, each head assembly having a like number of transducingelements that are aligned radially relative to a respective disksurface, when the post structure is fixed for file operation and datasignal transducing; the transducing elements of one post structure andthose of the other post structure of said one pair being diametricallyopposed and in transducing relation with the same data tracks to provideparallel data signal operation so that faster access is achieved; saidpost structures being pivotable so that said head assemblies may bemoved away and precisely back to the same positions such that saidtransducing elements are accurately aligned with the same data tracks asprior to rotation of the post structures.
 2. A magnetic disk storagefile as in claim 1, wherein two pairs of post structures are provided,each structure being spaced 90* apart from the adjacent structures, andcircumferentially around said spindle axis, and a like number ofmulti-element head assemblies mounted to each post structure, so thateach disk surface coacts in transducing relation with at least fourmulti-head assemblies that are circumferentially and equally spacedabout said axis.
 3. A magnetic disk storage file as in claim 2, whereinthe transducing elements mounted to one post structure are positionedover one set of data tracks and the transducing elements mounted toadjacent post structures are positioned over alternate interleaved datatracks.
 4. In a magnetic disk storage file as in claim 1, wherein saidhead assemblies are aligned in columns over said tracks, substantiallyparallel to the axis of said drive spindle.
 5. In a magnetic diskstorage file as in claim 1, further including a number of racks, eachrack carrying a plurality of said head assemblies and transducingelements, said racks being fastened to said post structures.
 6. In amagnetic disk storage file as in claim 1, including a pivot bearingassembly coupled to said housing and to said post structures, providinga pivot for said post structures.
 7. In a magnetic disk storage file asin claim 1, further including common circuit means, and electricalconnector means coupled to said multiplicity of magnetic headassemblies, said connector means coupling all of said head assemblies tosaid circuit means, so that selected ones of said transducing elementsmay be operative with said common circuit means at a given time.
 8. In amagnetic disk storage file as in claim 7, wherein said common circuitmeans is mounted to said post structures; and including a logicselection circuit coupled to said head assemblies, so that any ones ofsaid transducing elements may be selected to be energized and form aclosed circuit path in conjunction with said circuit means.
 9. In amagnetic disk storage file as in claim 1, the combination furtherincluding refrigeration and filtration means, providing an air flow andcooling through the disk area, thereby maintaining a clean airenvironment and a substantially constant temperature.
 10. In a magneticdisk storage file as in claim 9, further including an enclosure for saidfile, said disks and head assemblies being dIsposed within saidenclosure; closed loop means coupled to said enclosure for exhaustingair from the area of said disks; and temperature control means formaintaining the air within said enclosure at a substantially constanttemperature, said closed loop means providing a positive air flowoutwardly from said enclosure to ambient air when said enclosure isopened, to prevent entry of contaminants.
 11. In a magnetic disk storagefile as in claim 1, wherein said post structures include air ventsproviding access for air flow to said head assemblies, so that said headassemblies fly in relation to said rotary disks.
 12. In a magnetic diskstorage file as in claim 1, including a hub tool providing alignmentmeans for said post structures relative to the axis of said drivespindle, said hub tool being rotatable with said spindle.